It has been known that an alpha-ketoester group ##STR1## is a chemically active group which can be ester-exchanged with an active hydrogen containing-compound, such as an alcohol or an amine, or can be easily hydrolyzed.
If the alpha-ketoester group is introduced into a polymer, the polymer would be chemically interesting. In order to obtain such polymers, a compound which has both an alpha-ketoester group and a polymerizable double bond is required.
EP 20,000 B1 and NL 6612666 disclose number of a compounds which have both an alpha-ketoester group and a polymerizable double bond in the form of general formula, but actually synthetic examples are very few.